Ruler/mathematical aid



FIG. 1 is a top plan view of a ruler/mathematical aid showing our new design;

FIG. 2 is a right side elevational view, the left side elevational view being identical;

FIG. 3 is a front elevational view, the rear elevational view being identical; and

FIG. 4 is a bottom plan view thereof.

FIG. 5 shows the bottom plan view with cutout shapes thereon which is identical to the top plan view in FIG. 1 and is flat and unornamented. 

The ornamental design for a ruler/mathematical aid, as shown. 